When improvements or buildings are added to real estate, the real estate tax assessment is usually increased to reflect the increased value of the property. Frank Partipilo and Elmer Hallman owned neighboring tracts of land. Hallman made improvement to his land, constructing a new building and driveway on the tract. The tax assessor made a mistake about the location of the boundary line between Partipilo's and Hallman's land and thought the improvements were made on Partipilo's property. Instead of increasing the taxes on Hallman's land, the assessor wrongly increased the taxes on Partipilo's land. Partipilo paid the increased taxes for three years. When he learned why his taxes had been increased, he sued Hallman for the amount of the increase that Partipilo had been paying. Hallman raised the defense that he had not done anything wrong and that the mistake had been the fault of the tax assessor? Decide. [Partipilo v. Hallman, 510 N.E.2d 8 (Ill.App.)]